The present invention relates to a game apparatus, a game image preparation method and an information storage medium for games whose story branches as the game advances.
A game in which a character manipulated by a player (hereinafter referred to as “player character”) moves around in the game space, which is a virtual three-dimensional space, and clears a number of events that occur in the meantime is conventionally known. This kind of game is generally called an “action game,” and there is a predetermined course, which the player character follows, and various events occur while the player character is tracing the provided course. Moreover, a various ideas are often implemented so that when the player plays this game repeatedly the player can enjoy the game each time by introducing branches to this course and making the content of the game more complicated. For this purpose, each branched course is provided with three-dimensional objects with the greatest possible variations.
Moreover, recently, with increasingly faster processors, etc., techniques of expressing the game space using polygon graphics are generally used. In this case, each three-dimensional object in the game space is configured by polygons and these polygons are accompanied by textures, etc. as the occasion demands. While the player character is following a predetermined course, the viewpoint corresponding to the player also moves simultaneously. Perspective projection conversion is performed based on this viewpoint at a constant time interval (for example, 1/60-second interval), creating a two-dimensional image to be displayed on the display screen.
While it is possible to obtain a more realistic two-dimensional image by creating a game image using the technique of polygon graphics, making complicated figures appear more natural using polygons requires many polygons and textures for each three-dimensional object, thus producing a problem of requiring enormous effort to create data for background scene of the player character. Especially, when there are branches in the story of the game, it is necessary to provide a game space that varies from one course to another at the branch destination, which makes it necessary to create data for background that varies from one course to another and creating the data for background scene requires further effort.